Class 7

But how does this process (digestion) happen? Food is pushed through a long tube called the alimentary canal. At different spots along that tube special liquids (digestive juices) break big food pieces into tiny ones the body can use. What do you think is the role of saliva in your mouth? Saliva makes food wet … Read more

How was time measured when there were no clocks and watches? People watched events in nature that repeat—sunrise / sunset, phases of the Moon, seasons. To mark smaller parts of a day they made simple devices: Sundial – uses the Sun’s shadow. Water clock – water drips out (or fills a bowl) in fixed time. … Read more

In-text Questions Question: Why are cooking utensils generally made of metals? Answer: Cooking utensils are usually made of metals because metals are very good at letting heat pass through them. Materials that let heat pass easily are called good conductors. This helps the heat from the stove reach the food quickly and cook it properly. … Read more

Activity 6.1 – Looking at changes from Grade 5 to 8 Q 1. What were the most commonly observable changes among students? Height – most children grow taller. Weight / strength – many become heavier and stronger. Appearance – some boys show tiny moustache hair; some girls start to grow breasts; both may get pimples. … Read more

Activity 5.1 – Table of common changes Q (a) Complete Table 5.1 – what do you observe for each change? S. No. Change Simple observation 1 Melting ice cubes Ice becomes liquid water. 2 Chopping vegetables Large pieces become many small pieces. 3 Boiling water Water turns to steam (gas) and bubbles. 4 Making popcorn … Read more

4.1 Properties of Materials Activity 4.1 – Table 4.1: “Are they lustrous? Hard or soft? What happens when hammered?” S. No. Object / material Appearance Hard / soft Effect of hammering 1 Piece of copper Shiny (lustrous) Hard Flattens into a thin sheet 2 Piece of aluminium Shiny (lustrous) Hard Flattens into a thin sheet … Read more

1. Helping Nihal – uses of electricity Q 1 (a). Fill the blank lines in Nihal’s lists. Heading Some more items you can write Entertainment Video game console, music player Communication Land-line phone, e-mail device Lighting LED bulb, emergency lamp Cooking Electric rice-cooker, sandwich-maker Transportation Electric bicycle, airport escalator Heating & Cooling Water cooler Others … Read more

Activity 2.1 – Litmus test (Table 2.1) Question Fill the table after putting one drop of each sample on blue and red litmus paper. Answer S. No. Sample Blue litmus turns Red litmus turns 1 Lemon juice Red No change (stays red) 2 Soap solution No change (stays blue) Blue 3 Amla juice Red No … Read more